checkpoint work for SERVER-4644

1 files changed, 87 insertions, 0 deletions

diff --git a/src/mongo/util/trace.cpp b/src/mongo/util/trace.cpp
new file mode 100755
index 00000000000..db81952e9eb
--- /dev/null
+++ b/src/mongo/util/trace.cpp
@@ -0,0 +1,87 @@
+/**
+ * Copyright (c) 2012 10gen Inc.
+ *
+ * This program is free software: you can redistribute it and/or  modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "util/trace.h"
+
+namespace mongo {
+
+    /* the singleton static instance of this object */
+    Trace::NameMap *Trace::pMap = NULL;
+    SimpleRWLock Trace::lock("Trace");
+    Trace Trace::trace;
+
+    Trace::NameMap::NameMap():
+        traces() {
+    }
+
+    Trace::Trace() {
+        /*
+          This static singleton is constructed at program load time, so the
+          lock should not be necessary here.
+         */
+        Trace::pMap = new NameMap();
+    }
+
+    Trace::~Trace() {
+        delete Trace::pMap;
+    }
+
+    void Trace::setTrace(const string &name, unsigned level) {
+        SimpleRWLock::Exclusive xlock(Trace::lock); // dtor unlocks
+
+        /* if the new level is to be zero, we're going to remove the entry */
+        if (level == 0) {
+            Trace::pMap->traces.erase(name);
+            return;
+        }
+
+        /* try to insert the new trace */
+        std::pair<MapType::iterator, bool> i(
+            Trace::pMap->traces.insert(
+                MapType::value_type(name, level)));
+
+        /*
+          If the insert didn't take place, there was already an entry for
+          that name.  Set it to have the new level.
+         */
+        if (!i.second) {
+            (*i.first).second = level;
+        }
+    }
+
+#ifdef LATER
+    void Trace::setTraces(const string &names) {
+        /* create a new map, and replace the existing one */
+        NameMap *pM;
+        assert(false);
+    }
+#endif
+
+    unsigned Trace::getTrace(const string &name) {
+        SimpleRWLock::Shared slock(Trace::lock); // dtor unlocks
+
+        /* quickest check for no active traces */
+        if (Trace::pMap->traces.empty())
+            return 0;
+
+        /* there are traces, so look up by name */
+        MapType::const_iterator i(Trace::pMap->traces.find(name));
+        if (i == Trace::pMap->traces.end())
+            return 0;
+
+        return (*i).second;
+    }
+}